From 169501899b29af7e4d490f81206c69ae65cdb62f Mon Sep 17 00:00:00 2001
From: Dimitri Papadopoulos
 <3234522+DimitriPapadopoulos@users.noreply.github.com>
Date: Tue, 28 Apr 2026 13:38:19 +0200
Subject: [PATCH] Use f-strings

---
 src/zarr/core/buffer/core.py                  |  2 +-
 src/zarr/core/group.py                        |  2 +-
 src/zarr/registry.py                          |  2 +-
 src/zarr/storage/_fsspec.py                   |  4 +--
 src/zarr/storage/_memory.py                   |  8 ++---
 src/zarr/storage/_utils.py                    |  4 +--
 src/zarr/storage/_zip.py                      |  4 +--
 src/zarr/testing/store.py                     |  8 ++---
 src/zarr/testing/strategies.py                |  2 +-
 tests/conftest.py                             |  4 +--
 tests/test_api.py                             | 34 +++++++++----------
 tests/test_array.py                           |  2 +-
 tests/test_codec_entrypoints.py               |  4 +--
 tests/test_group.py                           | 22 ++++++------
 .../test_v2_dtype_regression.py               |  2 +-
 tests/test_store/test_memory.py               |  2 +-
 tests/test_store/test_zip.py                  |  2 +-
 17 files changed, 54 insertions(+), 54 deletions(-)

diff --git a/src/zarr/core/buffer/core.py b/src/zarr/core/buffer/core.py
index ddfb179213..58a59975b7 100644
--- a/src/zarr/core/buffer/core.py
+++ b/src/zarr/core/buffer/core.py
@@ -535,7 +535,7 @@ def all_equal(self, other: Any, equal_nan: bool = True) -> bool:
             and self._data.dtype.kind not in ("U", "S", "T", "O", "V")
         ):
             _data, other = np.broadcast_arrays(self._data, np.asarray(other, self._data.dtype))
-            void_dtype = "V" + str(_data.dtype.itemsize)
+            void_dtype = f"V{_data.dtype.itemsize}"
             return np.array_equal(_data.view(void_dtype), other.view(void_dtype))
         # use array_equal to obtain equal_nan=True functionality
         # Since fill-value is a scalar, isn't there a faster path than allocating a new array for fill value
diff --git a/src/zarr/core/group.py b/src/zarr/core/group.py
index 97f75c12bd..83a9cc6000 100644
--- a/src/zarr/core/group.py
+++ b/src/zarr/core/group.py
@@ -840,7 +840,7 @@ def name(self) -> str:
             # follow h5py convention: add leading slash
             name = self.path
             if name[0] != "/":
-                name = "/" + name
+                name = f"/{name}"
             return name
         return "/"
 
diff --git a/src/zarr/registry.py b/src/zarr/registry.py
index 8f3879a2a3..48f60fabd7 100644
--- a/src/zarr/registry.py
+++ b/src/zarr/registry.py
@@ -133,7 +133,7 @@ def _reload_config() -> None:
 
 def fully_qualified_name(cls: type) -> str:
     module = cls.__module__
-    return module + "." + cls.__qualname__
+    return f"{module}.{cls.__qualname__}"
 
 
 def register_codec(key: str, codec_cls: type[Codec], *, qualname: str | None = None) -> None:
diff --git a/src/zarr/storage/_fsspec.py b/src/zarr/storage/_fsspec.py
index 74e5869a66..1ca44a4e26 100644
--- a/src/zarr/storage/_fsspec.py
+++ b/src/zarr/storage/_fsspec.py
@@ -408,7 +408,7 @@ async def get_partial_values(
     async def list(self) -> AsyncIterator[str]:
         # docstring inherited
         allfiles = await self.fs._find(self.path, detail=False, withdirs=False)
-        for onefile in (a.removeprefix(self.path + "/") for a in allfiles):
+        for onefile in (a.removeprefix(f"{self.path}/") for a in allfiles):
             yield onefile
 
     async def list_dir(self, prefix: str) -> AsyncIterator[str]:
@@ -418,7 +418,7 @@ async def list_dir(self, prefix: str) -> AsyncIterator[str]:
             allfiles = await self.fs._ls(prefix, detail=False)
         except FileNotFoundError:
             return
-        for onefile in (a.replace(prefix + "/", "") for a in allfiles):
+        for onefile in (a.replace(f"{prefix}/", "") for a in allfiles):
             yield onefile.removeprefix(self.path).removeprefix("/")
 
     async def list_prefix(self, prefix: str) -> AsyncIterator[str]:
diff --git a/src/zarr/storage/_memory.py b/src/zarr/storage/_memory.py
index 53d3cfbfde..bd91029732 100644
--- a/src/zarr/storage/_memory.py
+++ b/src/zarr/storage/_memory.py
@@ -217,9 +217,9 @@ async def list_dir(self, prefix: str) -> AsyncIterator[str]:
             # a pseudo directory when there's a nested item and we're listing an
             # intermediate level.
             keys_unique = {
-                key.removeprefix(prefix + "/").split("/")[0]
+                key.removeprefix(f"{prefix}/").split("/")[0]
                 for key in self._store_dict
-                if key.startswith(prefix + "/") and key != prefix
+                if key.startswith(f"{prefix}/") and key != prefix
             }
 
         for key in keys_unique:
@@ -822,7 +822,7 @@ async def delete(self, key: str) -> None:
 
     async def list(self) -> AsyncIterator[str]:
         # docstring inherited
-        prefix = self.path + "/" if self.path else ""
+        prefix = f"{self.path}/" if self.path else ""
         async for key in super().list():
             if key.startswith(prefix):
                 yield key.removeprefix(prefix)
@@ -832,7 +832,7 @@ async def list_prefix(self, prefix: str) -> AsyncIterator[str]:
         # Manual concatenation instead of _join_paths because we need "path/"
         # as the prefix when prefix is empty (to list all keys under self.path)
         full_prefix = f"{self.path}/{prefix}" if self.path else prefix
-        path_prefix = self.path + "/" if self.path else ""
+        path_prefix = f"{self.path}/" if self.path else ""
         async for key in super().list_prefix(full_prefix):
             yield key.removeprefix(path_prefix)
 
diff --git a/src/zarr/storage/_utils.py b/src/zarr/storage/_utils.py
index 722a2d3568..2ff9baa5ab 100644
--- a/src/zarr/storage/_utils.py
+++ b/src/zarr/storage/_utils.py
@@ -220,10 +220,10 @@ def _relativize_path(*, path: str, prefix: str) -> str:
     if prefix == "":
         return path
     else:
-        _prefix = prefix + "/"
+        _prefix = f"{prefix}/"
         if not path.startswith(_prefix):
             raise ValueError(f"The first component of {path} does not start with {prefix}.")
-        return path.removeprefix(f"{prefix}/")
+        return path.removeprefix(_prefix)
 
 
 def _normalize_paths(paths: Iterable[str]) -> tuple[str, ...]:
diff --git a/src/zarr/storage/_zip.py b/src/zarr/storage/_zip.py
index c5c7cbf3e8..897797e999 100644
--- a/src/zarr/storage/_zip.py
+++ b/src/zarr/storage/_zip.py
@@ -285,8 +285,8 @@ async def list_dir(self, prefix: str) -> AsyncIterator[str]:
                     yield key
         else:
             for key in keys:
-                if key.startswith(prefix + "/") and key.strip("/") != prefix:
-                    k = key.removeprefix(prefix + "/").split("/")[0]
+                if key.startswith(f"{prefix}/") and key.strip("/") != prefix:
+                    k = key.removeprefix(f"{prefix}/").split("/")[0]
                     if k not in seen:
                         seen.add(k)
                         yield k
diff --git a/src/zarr/testing/store.py b/src/zarr/testing/store.py
index 91c174b589..a0bbe6b4b2 100644
--- a/src/zarr/testing/store.py
+++ b/src/zarr/testing/store.py
@@ -449,8 +449,8 @@ async def test_list(self, store: S) -> None:
         prefix = "foo"
         data = self.buffer_cls.from_bytes(b"")
         store_dict = {
-            prefix + "/zarr.json": data,
-            **{prefix + f"/c/{idx}": data for idx in range(10)},
+            f"{prefix}/zarr.json": data,
+            **{f"{prefix}/c/{idx}": data for idx in range(10)},
         }
         await store._set_many(store_dict.items())
         expected_sorted = sorted(store_dict.keys())
@@ -536,10 +536,10 @@ async def test_list_dir(self, store: S) -> None:
             await store._set_many(store_dict.items())
 
             keys_observed = await _collect_aiterator(store.list_dir(root))
-            keys_expected = {k.removeprefix(root + "/").split("/")[0] for k in store_dict}
+            keys_expected = {k.removeprefix(f"{root}/").split("/")[0] for k in store_dict}
             assert sorted(keys_observed) == sorted(keys_expected)
 
-            keys_observed = await _collect_aiterator(store.list_dir(root + "/"))
+            keys_observed = await _collect_aiterator(store.list_dir(f"{root}/"))
             assert sorted(keys_expected) == sorted(keys_observed)
 
     async def test_set_if_not_exists(self, store: S) -> None:
diff --git a/src/zarr/testing/strategies.py b/src/zarr/testing/strategies.py
index 3bb059b3a8..1b0ede1148 100644
--- a/src/zarr/testing/strategies.py
+++ b/src/zarr/testing/strategies.py
@@ -323,7 +323,7 @@ def arrays(
         assert a.fill_value is not None
     assert a.name is not None
     assert a.path == normalize_path(array_path)
-    assert a.name == "/" + a.path
+    assert a.name == f"/{a.path}"
     assert isinstance(root[array_path], Array)
     assert nparray.shape == a.shape
 
diff --git a/tests/conftest.py b/tests/conftest.py
index de1730fff9..6577f8afa0 100644
--- a/tests/conftest.py
+++ b/tests/conftest.py
@@ -87,7 +87,7 @@ async def parse_store(
     if store == "fsspec":
         return await FsspecStore.open(url=path)
     if store == "zip":
-        return await ZipStore.open(path + "/zarr.zip", mode="w")
+        return await ZipStore.open(f"{path}/zarr.zip", mode="w")
     if store == "memory_get_latency":
         return LatencyStore(MemoryStore(), get_latency=0.0001, set_latency=0)
     raise AssertionError
@@ -143,7 +143,7 @@ async def store2(request: pytest.FixtureRequest, tmpdir: LEGACY_PATH) -> Store:
 def sync_store(request: pytest.FixtureRequest, tmp_path: LEGACY_PATH) -> Store:
     result = sync(parse_store(request.param, str(tmp_path)))
     if not isinstance(result, Store):
-        raise TypeError("Wrong store class returned by test fixture! got " + result + " instead")
+        raise TypeError(f"Wrong store class returned by test fixture! got {result} instead")
     return result
 
 
diff --git a/tests/test_api.py b/tests/test_api.py
index 4198d56c78..d8c4d20f4a 100644
--- a/tests/test_api.py
+++ b/tests/test_api.py
@@ -822,9 +822,9 @@ def test_tree() -> None:
 #             assert len(source) == len(dest)
 #             for key in source:
 #                 if self._version == 3:
-#                     dest_key = key[:10] + "new/" + key[10:]
+#                     dest_key = f"{key[:10]}new/{key[10:]}"
 #                 else:
-#                     dest_key = "new/" + key
+#                     dest_key = f"new/{key}"
 #                 assert source[key] == dest[dest_key]
 
 #     def test_source_dest_path(self):
@@ -841,7 +841,7 @@ def test_tree() -> None:
 #                         assert source[key] == dest[dest_key]
 #                     else:
 #                         assert key not in dest
-#                         assert ("new/" + key) not in dest
+#                         assert (f"new/{key}") not in dest
 
 #     def test_excludes_includes(self):
 #         source = self.source
@@ -853,16 +853,16 @@ def test_tree() -> None:
 #         assert len(dest) == 2
 
 #         root = ""
-#         assert root + "foo" not in dest
+#         assert "f{root}foo" not in dest
 
 #         # multiple excludes
 #         dest = self._get_dest_store()
 #         excludes = "b.z", ".*x"
 #         copy_store(source, dest, excludes=excludes)
 #         assert len(dest) == 1
-#         assert root + "foo" in dest
-#         assert root + "bar/baz" not in dest
-#         assert root + "bar/qux" not in dest
+#         assert f"{root}foo" in dest
+#         assert f"{root}bar/baz" not in dest
+#         assert f"{root}bar/qux" not in dest
 
 #         # excludes and includes
 #         dest = self._get_dest_store()
@@ -870,9 +870,9 @@ def test_tree() -> None:
 #         includes = ".*x"
 #         copy_store(source, dest, excludes=excludes, includes=includes)
 #         assert len(dest) == 2
-#         assert root + "foo" in dest
-#         assert root + "bar/baz" not in dest
-#         assert root + "bar/qux" in dest
+#         assert f"{root}foo" in dest
+#         assert f"{root}bar/baz" not in dest
+#         assert f"{root}bar/qux" in dest
 
 #     def test_dry_run(self):
 #         source = self.source
@@ -884,7 +884,7 @@ def test_tree() -> None:
 #         source = self.source
 #         dest = self._get_dest_store()
 #         root = ""
-#         dest[root + "bar/baz"] = b"mmm"
+#         dest[f"{root}bar/baz"] = b"mmm"
 
 #         # default ('raise')
 #         with pytest.raises(CopyError):
@@ -897,16 +897,16 @@ def test_tree() -> None:
 #         # skip
 #         copy_store(source, dest, if_exists="skip")
 #         assert 3 == len(dest)
-#         assert dest[root + "foo"] == b"xxx"
-#         assert dest[root + "bar/baz"] == b"mmm"
-#         assert dest[root + "bar/qux"] == b"zzz"
+#         assert dest[f"{root}foo"] == b"xxx"
+#         assert dest[f"{root}bar/baz"] == b"mmm"
+#         assert dest[f"{root}bar/qux"] == b"zzz"
 
 #         # replace
 #         copy_store(source, dest, if_exists="replace")
 #         assert 3 == len(dest)
-#         assert dest[root + "foo"] == b"xxx"
-#         assert dest[root + "bar/baz"] == b"yyy"
-#         assert dest[root + "bar/qux"] == b"zzz"
+#         assert dest[f"{root}foo"] == b"xxx"
+#         assert dest[f"{root}bar/baz"] == b"yyy"
+#         assert dest[f"{root}bar/qux"] == b"zzz"
 
 #         # invalid option
 #         with pytest.raises(ValueError):
diff --git a/tests/test_array.py b/tests/test_array.py
index f7f564f30e..132c4c26c3 100644
--- a/tests/test_array.py
+++ b/tests/test_array.py
@@ -1645,7 +1645,7 @@ async def test_name(store: Store, zarr_format: ZarrFormat, path: str | None) ->
         else:
             expected_path = path
         assert arr.path == expected_path
-        assert arr.name == "/" + expected_path
+        assert arr.name == f"/{expected_path}"
 
         # test that implicit groups were created
         path_parts = expected_path.split("/")
diff --git a/tests/test_codec_entrypoints.py b/tests/test_codec_entrypoints.py
index fc7b79fe54..69cd0a1577 100644
--- a/tests/test_codec_entrypoints.py
+++ b/tests/test_codec_entrypoints.py
@@ -7,7 +7,7 @@
 @pytest.mark.usefixtures("set_path")
 @pytest.mark.parametrize("codec_name", ["TestEntrypointCodec", "TestEntrypointGroup.Codec"])
 def test_entrypoint_codec(codec_name: str) -> None:
-    config.set({"codecs.test": "package_with_entrypoint." + codec_name})
+    config.set({"codecs.test": f"package_with_entrypoint.{codec_name}"})
     cls_test = zarr.registry.get_codec_class("test")
     assert cls_test.__qualname__ == codec_name
 
@@ -24,7 +24,7 @@ def test_entrypoint_pipeline() -> None:
 def test_entrypoint_buffer(buffer_name: str) -> None:
     config.set(
         {
-            "buffer": "package_with_entrypoint." + buffer_name,
+            "buffer": f"package_with_entrypoint.{buffer_name}",
             "ndbuffer": "package_with_entrypoint.TestEntrypointNDBuffer",
         }
     )
diff --git a/tests/test_group.py b/tests/test_group.py
index f9b3a208a8..e05df0dfcb 100644
--- a/tests/test_group.py
+++ b/tests/test_group.py
@@ -66,7 +66,7 @@
 async def store(request: pytest.FixtureRequest, tmpdir: LEGACY_PATH) -> Store:
     result = await parse_store(request.param, str(tmpdir))
     if not isinstance(result, Store):
-        raise TypeError("Wrong store class returned by test fixture! got " + result + " instead")
+        raise TypeError(f"Wrong store class returned by test fixture! got {result} instead")
     return result
 
 
@@ -150,7 +150,7 @@ def test_group_name_properties(
     """
     root = Group.from_store(store=StorePath(store=store, path=root_name), zarr_format=zarr_format)
     assert root.path == normalize_path(root_name)
-    assert root.name == "/" + root.path
+    assert root.name == f"/{root.path}"
     assert root.basename == root.path
 
     branch = root.create_group(branch_name)
@@ -158,7 +158,7 @@ def test_group_name_properties(
         assert branch.path == normalize_path(branch_name)
     else:
         assert branch.path == "/".join([root.path, normalize_path(branch_name)])
-    assert branch.name == "/" + branch.path
+    assert branch.name == f"/{branch.path}"
     assert branch.basename == branch_name.split("/")[-1]
 
 
@@ -732,7 +732,7 @@ def test_group_create_array(
             a[:] = data
 
     assert array.path == normalize_path(name)
-    assert array.name == "/" + array.path
+    assert array.name == f"/{array.path}"
     assert array.shape == shape
     assert array.dtype == np.dtype(dtype)
     assert np.array_equal(array[:], data)
@@ -1082,10 +1082,10 @@ async def test_asyncgroup_delitem(store: Store, zarr_format: ZarrFormat) -> None
 
     #  todo: clean up the code duplication here
     if zarr_format == 2:
-        assert not await agroup.store_path.store.exists(array_name + "/" + ".zarray")
-        assert not await agroup.store_path.store.exists(array_name + "/" + ".zattrs")
+        assert not await agroup.store_path.store.exists(f"{array_name}/.zarray")
+        assert not await agroup.store_path.store.exists(f"{array_name}/.zattrs")
     elif zarr_format == 3:
-        assert not await agroup.store_path.store.exists(array_name + "/" + "zarr.json")
+        assert not await agroup.store_path.store.exists(f"{array_name}/zarr.json")
     else:
         raise AssertionError
 
@@ -1093,10 +1093,10 @@ async def test_asyncgroup_delitem(store: Store, zarr_format: ZarrFormat) -> None
     _ = await agroup.create_group(sub_group_path, attributes={"foo": 100})
     await agroup.delitem(sub_group_path)
     if zarr_format == 2:
-        assert not await agroup.store_path.store.exists(array_name + "/" + ".zgroup")
-        assert not await agroup.store_path.store.exists(array_name + "/" + ".zattrs")
+        assert not await agroup.store_path.store.exists(f"{array_name}/.zgroup")
+        assert not await agroup.store_path.store.exists(f"{array_name}/.zattrs")
     elif zarr_format == 3:
-        assert not await agroup.store_path.store.exists(array_name + "/" + "zarr.json")
+        assert not await agroup.store_path.store.exists(f"{array_name}/zarr.json")
     else:
         raise AssertionError
 
@@ -1113,7 +1113,7 @@ async def test_asyncgroup_create_group(
 
     assert isinstance(subgroup, AsyncGroup)
     assert subgroup.path == normalize_path(name)
-    assert subgroup.name == "/" + subgroup.path
+    assert subgroup.name == f"/{subgroup.path}"
     assert subgroup.attrs == attributes
     assert subgroup.store_path.path == subgroup.path
     assert subgroup.store_path.store == store
diff --git a/tests/test_regression/test_v2_dtype_regression.py b/tests/test_regression/test_v2_dtype_regression.py
index 2607f9aa36..c7b4a53a52 100644
--- a/tests/test_regression/test_v2_dtype_regression.py
+++ b/tests/test_regression/test_v2_dtype_regression.py
@@ -216,7 +216,7 @@ def test_roundtrip_v2(source_array_v2: ArrayV2, tmp_path: Path, script_path: Pat
         capture_output=True,
         text=True,
     )
-    assert copy_op.returncode == 0, "stdout " + copy_op.stdout + "\n stderr" + copy_op.stderr
+    assert copy_op.returncode == 0, f"stdout {copy_op.stdout}\n stderr{copy_op.stderr}"
     out_array = zarr.open_array(store=out_path, mode="r", zarr_format=2)
     assert source_array_v2.metadata.to_dict() == out_array.metadata.to_dict()
     assert np.array_equal(source_array_v2[:], out_array[:])
diff --git a/tests/test_store/test_memory.py b/tests/test_store/test_memory.py
index 4ffc15a87b..92e292bef1 100644
--- a/tests/test_store/test_memory.py
+++ b/tests/test_store/test_memory.py
@@ -380,7 +380,7 @@ def test_from_url(self, store: ManagedMemoryStore) -> None:
 
     def test_from_url_with_path(self, store: ManagedMemoryStore) -> None:
         """Test that from_url extracts path component from URL."""
-        url = str(store) + "/some/path"
+        url = f"{store}/some/path"
         store2 = ManagedMemoryStore.from_url(url)
         assert store2._store_dict is store._store_dict
         assert store2.path == "some/path"
diff --git a/tests/test_store/test_zip.py b/tests/test_store/test_zip.py
index 5975a6d2a0..be51bcedcb 100644
--- a/tests/test_store/test_zip.py
+++ b/tests/test_store/test_zip.py
@@ -147,7 +147,7 @@ async def test_list_without_explicit_open(self, tmp_path: Path) -> None:
         root = zarr.open_group(store=zarr_path, mode="w")
         root["x"] = np.array([1, 2, 3])
         shutil.make_archive(str(zarr_path), "zip", zarr_path)
-        shutil.move(str(zarr_path) + ".zip", zip_path)
+        shutil.move(f"{zarr_path}.zip", zip_path)
 
         store = ZipStore(zip_path, mode="r")
         assert not store._is_open